|HARVESON, ROBERT - University Of Nebraska|
|NELSON, ALLAN - Tarleton State University|
|MATHEW, FEBINA - South Dakota State University|
Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2015
Publication Date: 11/25/2015
Citation: Harveson, R.M, Nelson, A., Mathew, F.M., Seiler, G.J. 2015. First report of Orobanche ludoviciana parasitizing sunflowers. Plant Health Progress. 16(4):216-217. doi:10.1094/PHP-BR-15-0043.
Interpretive Summary: Global sunflower production is challenged by a number of pests that reduce yield. Broomrape is the common name given to a group of flowering plants belonging to the genus Orobanche that are obligate parasites that lack chlorophyll and depend upon their host for nutrition by parasitizing the vascular system of plant roots, absorbing nutrients and water, thus causing stunting, reduced growth and severe yield reductions. Broomrape is major constraint to sunflower production in many regions of Europe, particularly in those countries that border the Mediterranean and Black Seas, but not in the Americas. A species of broomrape, Louisiana broomrape was found parasitizing sunflowers in a field in Nebraska. This species is indigenous to the Great Plains from Canada south to Texas with a natural habitat of dry, sandy upland prairies, with hosts being several members of the Composite family such as ragweed, cocklebur, and sagebrush. Fortunately, Louisiana broomrape is not related to the devastating European species that plagues sunflower production in other parts of the world. However, Louisiana broomrape could still potentially present problems for sunflower growers throughout the Great Plains due to the fact that the parasite is native to and widely dispersed throughout this region.
Technical Abstract: Broomrape is the common name given to a group of flowering plants belonging to the genus Orobanche that parasitize the roots of higher dicotyledonous plants. More than 100 species of Orobanche have been identified, all of which are obligate parasites that lack chlorophyll and depend upon their host for nutrition. After establishing connections with the vascular system of their hosts, broomrapes draw nutrients and water from roots or other underground parts of hosts after infection. Broomrapes are a major constraint to sunflower production in many regions of Europe, particularly in those countries that border the Mediterranean Sea and Black Sea. The most widespread and common broomrape species that attacks sunflower is Orobanche cumana. In early September, 2014, a commercial sunflower production field in Kimball County, Nebraska was found with numerous, unknown plants with purple to blue flowers emerging from the soil and associated with the base of sunflower plants. Estimated incidences of 30% of plants were clustered in one particular area comprising approximately 25% of the total area of the field. The unknown plants were found parasitizing the roots of the sunflower plants, and were identified as Orobanche ludoviciana (Louisiana broomrape) using both morphological characteristics and molecular analyses. To our knowledge, this is the first report for any Orobanche species found parasitizing commercial sunflowers in the western hemisphere. Fortunately, this report is not related to the species that is most economically damaging in Europe (O. cumana); however, it could still potentially present problems for sunflower growers throughout the Great Plains due to the fact that the parasite is native to and widely dispersed throughout this region.